Structural-dependent Performance of Au Nano-Wire Blended D-Shaped SPR Sensors

Surface Plasmon Resonance (SPR) is one of the promising techniques in the field of refractive index sensing, which assists in achieving ultra-high sensitivity, real-time, label-free detection with versatile chemical and biochemical sensing capabilities. The SPR phenomenon is the oscillation of electrons in a metal-dielectric interface with incident light. This study thoroughly evaluates the performance of a D-shaped single-mode optical fiber-based SPR sensor with different shapes of gold nano-wire to enhance the detection sensitivity. Four different nano-wires-based sensors including circular-shaped, square-shaped, triangular-shaped, and rectangular-shaped are investigated. The maximum wavelength sensitivities found are 50,000 nm/RIU, 40,000 nm/RIU, 40,000 nm/RIU, and 60,000 nm/RIU for circular, square, triangular, and rectangular nano-wires-based SPR sensors, respectively. In addition, comprehensive investigations show that the maximum amplitude sensitivities for circular, square, triangular, and rectangular nano-wire are 71.871 RIU^-1, 23.615 RIU^-1, 23.661 RIU^-1, and 59.558 RIU^-1, respectively. The RI range of 1.40 to 1.405 covers the polyacrylonitrile liquid which combines the binary mixtures of acrylonitrile with ethanol, methanol, propan-1-ol, etc., where we discovered the highest sensitivity.